Quick Answer: How to Point or Repoint an Indian Sandstone Patio
To point or repoint an Indian sandstone patio, remove all loose or failed old jointing, clean the joints properly, and refill the gaps with a suitable wet mortar, brush-in compound or resin-based jointing product. For most Indian sandstone patios, a joint width of around 10 mm to 15 mm is practical because it allows the jointing material to be compacted properly while still giving the patio a traditional natural stone appearance.
The most important rule is to protect the face of the sandstone. Indian sandstone is porous, so mortar, cement residue, resin film or jointing compound should never be allowed to dry on the slab surface. Cement staining on sandstone is one of the most common problems customers ask about, and prevention is far easier than removal.
The best jointing method depends on the joint width, joint depth, bedding condition, drainage, exposure and the experience of the person doing the work. Wet mortar gives a traditional strong joint when done properly. Brush-in jointing compound is easier for many DIY users. Resin-based jointing can give a harder professional finish, but it has stricter application conditions.
Pointing vs Repointing: What Is the Difference?
Pointing means filling and finishing the joints between paving slabs when the patio is first laid. Repointing means removing failed, cracked, loose or washed-out old jointing and replacing it with new material later.
The two jobs are similar, but repointing involves more preparation. Before any new jointing compound can be added, the old failed material must be removed. If this is not done properly, the new jointing may sit on top of loose dust and broken mortar, then crack, wash out or fail again.
Repointing is common on older Indian sandstone patios, especially where the joints have been weakened by age, frost, weeds, poor original pointing or repeated pressure washing. If the joints are hollow, crumbling, full of weeds or missing in places, repointing is usually needed.
Repointing Is Not the Same as Re-Laying
Before starting, it is important to understand what repointing can and cannot fix. Repointing replaces the material between the paving slabs. It does not repair a failed sub-base, poor bedding or slabs that are loose and rocking.
If the slabs are firm and stable, repointing may be all that is needed. If the slabs move, rock, sink or sound hollow when tapped, the problem is likely underneath the slab. In that situation, new jointing compound alone will not solve the issue, because the movement will usually crack the new joint again.
The simple test is to walk across the patio and check each slab. If the paving is stable and only the joints have failed, repointing is suitable. If the slabs are unstable, the affected slabs may need to be lifted and re-bedded by an installer before the joints are redone.
Preparing the Joints Before Pointing
Good pointing starts with preparation. The joint must be deep enough, clean enough and stable enough to hold the new material. If the joint is shallow, dusty or partly filled with loose old mortar, the new jointing will usually fail early.
Remove all failed material from the joints. This may be done with a joint scraper, weeding knife, plugging chisel, bolster or, for harder old mortar, an angle grinder with a suitable mortar-raking blade. Work carefully because Indian sandstone edges can chip if tools are forced against the slab.
Once the old jointing has been removed, brush, vacuum or blow out loose dust and debris. If necessary, rinse the joints with clean water to remove fine dust from the slab edges. The joints should then be allowed to reach the correct wet or dry condition required by the chosen jointing method.
Choosing a Jointing Method
There is no single best jointing method for every Indian sandstone patio. The right choice depends on joint size, joint depth, bedding condition, expected traffic, drainage, budget and the finish required.
| Jointing Method | Best For | Advantages | Limitations | DIY Suitability |
|---|---|---|---|---|
| Wet mortar pointing | Traditional patios, wider joints and stronger hand-finished joints | Cost-effective, strong when compacted properly, classic appearance | Needs skill; cement residue can stain sandstone if left on the surface | Moderate |
| Brush-in jointing compound | Domestic patios, faster re-jointing and many DIY jobs | Quicker to apply, cleaner than mortar when used correctly, easier for homeowners | More expensive than sand and cement; must follow exact wet or dry instructions | Good |
| Resin-based jointing compound | Higher-quality finishes, stronger joints and more demanding patio areas | Durable, tidy finish, good resistance to weeds and weather when applied correctly | Higher cost, strict application conditions, residue must be removed immediately | Moderate to professional |
| Kiln-dried or polymeric sand | Very narrow joints and light-use areas only | Simple and low cost | Usually not suitable for normal wide Indian sandstone patio joints | Easy, but limited use |
Wet Mortar Pointing
Wet mortar pointing is the traditional method. It is usually made with cement and sand, placed into the joints with a pointing trowel, compacted firmly and finished neatly. A common mix is 1 part cement to 3 parts plastering sand for a finer pointing mortar. Some installers also use around 4 parts sharp sand to 1 part cement for a stronger, coarser wet mix, depending on joint size and the required finish.
The mix should be workable but not wet and sloppy. It should hold together and be pressed into the joint, not smeared across the face of the stone. Wet mortar can create a strong traditional joint, but it requires care because cement staining on Indian sandstone can be difficult to remove.
Brush-In Jointing Compound
Brush-in jointing compound is popular for domestic patios because it is faster and easier than traditional mortar pointing. It is normally swept diagonally into the joints and topped up until the gaps are full. Many products are designed for use with water, while some have different requirements.
The key point is to follow the manufacturer's instructions exactly. Some brush-in compounds require the paving to be soaked and kept wet during application so residue does not stick to the stone surface. Other products may require different conditions. Never assume all brush-in compounds work the same way.
Resin-Based Jointing Compound
Resin-based jointing compounds can give a stronger and more professional finish, but they are less forgiving. Some resin systems must not be applied to damp stone or damp joints, and they should not be used if rain is forecast within the curing period. As a cautious rule, avoid applying dry-use resin jointing products if rain is forecast within 24 hours, unless the product manufacturer clearly states otherwise.
Resin residue must be removed from the sandstone surface before it cures. Once hardened, resin film or staining can be difficult to remove. Always check whether the product is suitable for natural sandstone and whether the paving needs to be dry, damp or wet before application.
Step-by-Step Guide to Wet Mortar Pointing
Step 1: Remove the Old Jointing
Remove all loose, cracked, crumbling or failed jointing material. This is often the slowest part of the job, but it is essential. New jointing should not be applied over weak old material.
For soft, degraded joints, a joint scraper, hooked tool or weeding knife may be enough. For harder mortar joints, a plugging chisel, bolster or angle grinder may be needed. Work slowly and avoid damaging the edges of the sandstone slabs.
Step 2: Clean the Joint Properly
Brush, vacuum or blow out dust, grit, weeds, loose mortar and broken jointing compound. Any dusty or loose material left in the joint can stop the new mortar from sitting and curing properly.
If an angle grinder has been used, rinse the joints carefully with clean water to remove fine dust from the joint walls and slab edges. Allow the patio to dry back to the condition needed for mortar pointing.
Step 3: Mix the Mortar
For a traditional fine pointing mortar, use around 1 part cement to 3 parts plastering sand. For a stronger, coarser wet mix, some installers use around 4 parts sharp sand to 1 part cement. The right mix depends on the joint size, finish required and installer preference.
The mortar should be damp and workable, not runny. If the mix is too wet, it is more likely to smear over the stone and cause staining. If it is too dry, it may not compact properly inside the joint.
Step 4: Press the Mortar into the Joints
Use a pointing trowel or jointing tool to place the mortar directly into the joints. Press it down firmly so there are no air pockets. Do not brush dry or semi-dry cement mix across the sandstone surface.
Work in small sections. Keep the slab surface clean as you go. If mortar touches the face of the sandstone, remove it before it begins to harden.
Step 5: Strike and Finish the Joints
Use a pointing trowel or jointing iron to compact and smooth the joint. A slightly concave finish is often preferred because it sheds water well and gives a tidy traditional appearance.
The finished joint should sit slightly below the top surface of the paving, not proud of the slab face. Joints that are too high can look messy and hold dirt. Joints that are too low may collect soil and weed seeds.
Step 6: Clean the Sandstone Surface
Clean any mortar residue immediately before it dries. Do not leave cement haze, smears or splashes on the sandstone face. Once cement residue hardens on porous sandstone, removal can be difficult and may require specialist cleaning.
Step 7: Protect the New Joints While They Cure
Fresh mortar should be protected from heavy rain, frost, strong sun and rapid drying. Keep people, pets and garden furniture off the patio while the joints cure. The exact curing time depends on the weather and mix, but the patio should not be pressure washed until the mortar has fully hardened.
Joint Width Guidance for Indian Sandstone
Indian sandstone is normally laid with wider joints than porcelain because it is a natural stone with hand-cut or lightly dressed edges. For most riven Indian sandstone patios, joints around 10 mm to 15 mm are practical and visually suitable.
| Joint Width | Suitability | Guidance |
|---|---|---|
| Under 5 mm | Usually too narrow for normal Indian sandstone | May only suit very narrow-joint systems or kiln-dried/polymeric sand, depending on the product. Not ideal for typical hand-cut sandstone. |
| 5 mm to 10 mm | Possible with selected products | Some brush-in or resin products may work, but always check the product's minimum width and depth. |
| 10 mm to 15 mm | Recommended practical range | Suitable for most riven Indian sandstone patios and allows mortar or compound to be compacted properly. |
| Over 15 mm | Possible, but needs more care | Wider joints need more material and careful compaction. Poorly filled wide joints may crack, wash out or collect dirt. |
Joint depth is also important. Many jointing products require a depth of at least around 20 mm, and some need more. Thicker calibrated sandstone can create deeper joints, which means more compound is needed and the joint must be filled properly from the bottom, not just skimmed over at the surface.
Keeping the Sandstone Clean During Pointing
Keeping the stone clean is as important as filling the joints. Sandstone is porous and textured, so cement, resin or compound residue can sit in the surface and leave staining or haze.
- Work in small, manageable sections.
- Do not spread wet mortar across the slab face.
- Remove spills and smears immediately.
- Use clean tools and clean water.
- Follow the product's cleaning instructions exactly.
- Do not allow cement or resin residue to dry on the stone.
If cement residue dries on the stone, do not immediately use strong acid cleaner. Many acid cleaners can damage natural sandstone or alter its surface. Use a suitable natural stone cleaner and follow professional advice where staining is severe.
Common Pointing Mistakes to Avoid
| Mistake | Possible Result | Better Approach |
|---|---|---|
| Leaving loose old jointing in place | New jointing fails early | Rake or cut out failed material properly |
| Using joints that are too shallow | Compound cracks or washes out | Clean the joint to the required depth |
| Brushing dry cement mix over sandstone | Staining and weak joints | Use proper wet mortar pointing or a suitable compound |
| Pointing over wet stone with mortar | Smearing, staining and poor finish | Use the correct surface condition for the chosen method |
| Applying dry-use resin compound to damp joints | Joint failure, haze or poor curing | Only apply resin in the conditions stated by the manufacturer |
| Using resin when rain is forecast | Washed joints, curing failure or surface residue | Avoid application if rain is forecast within the product's curing period |
| Pointing over a moving slab | New joints crack again | Lift and re-bed unstable slabs before repointing |
| Sealing before the jointing has cured | Trapped moisture, patchy colour or curing problems | Allow the jointing to cure fully before sealing |
| Pressure washing too soon | New joints are damaged | Allow full curing time before any pressure washing |
Can You Point Indian Sandstone with Sand and Cement?
Yes, Indian sandstone can be pointed with a suitable sand and cement mortar, but it must be done carefully. A common fine pointing mix is 1 part cement to 3 parts plastering sand. Some installers use 4 parts sharp sand to 1 part cement for a stronger wet mortar mix, especially where joints are larger.
The mortar should be placed into the joints with a trowel, compacted and finished neatly. It should not be brushed dry across the surface of the slabs. Dry or semi-dry cement brushing can stain sandstone and usually does not create a proper durable joint.
Traditional mortar pointing can produce a strong, clean and long-lasting joint, but it takes more skill than brush-in compound. The biggest risk is cement staining on the sandstone face.
Can You Use Brush-In Jointing Compound on Indian Sandstone?
Yes, many brush-in jointing compounds are suitable for Indian sandstone patios, provided the product is compatible with natural stone and the joint size meets the manufacturer's requirements.
Brush-in compounds are popular because they are quicker to apply and easier for many homeowners than traditional mortar pointing. However, they are not all the same. Some require the patio to be soaked and kept wet during application. Others have different curing and cleaning requirements. Always read the product instructions before starting.
On sandstone, surface staining is the main concern. Keep the stone surface in the condition required by the product, remove all excess material, and do not leave compound residue to harden on the face of the slabs.
Should Indian Sandstone Be Sealed After Repointing?
Sealing after repointing is optional. It is not required for every patio, but it can be useful if the customer wants easier cleaning and improved resistance to some stains. For more detail, see our guide on whether Indian sandstone should be sealed.
Before sealing, both the sandstone and the new joints must be fully cured, clean and dry. Sealing too soon can trap moisture, affect curing or create patchy colour. The waiting time depends on the jointing material, weather and sealer manufacturer's instructions.
A breathable impregnating sealer is usually more suitable for natural sandstone than a heavy surface coating. It can reduce water absorption and make routine maintenance easier, but it will not make the patio maintenance-free. It may also slightly deepen the colour, so a small test area is always recommended.
Pressure Washing After Repointing
Pressure washing should be avoided until the jointing material has fully cured. Some brush-in products may require at least 14 days before pressure washing, and some mortar or resin systems may need longer. Always follow the manufacturer's curing guidance.
When pressure washing is safe, use sensible pressure, a wide fan nozzle and a shallow angle. Avoid blasting directly into the joints. For wider maintenance guidance, see our article on pressure washing Indian sandstone patios.
Final Recommendation
Pointing or repointing an Indian sandstone patio is mainly about preparation and cleanliness. The old failed material must be removed, the joints must be clean and deep enough, and the new mortar or compound must be suitable for natural stone.
For a traditional finish, wet mortar pointing can work very well when carried out carefully. For many domestic patios, a good brush-in jointing compound may be easier and cleaner, provided the surface is kept wet or dry exactly as the manufacturer requires. For stronger professional-style joints, resin-based systems may be suitable, but only when the application conditions are correct.
The key rule is simple: protect the sandstone face. Do not smear cement, mortar, resin or compound across the slabs and leave it to dry. Prepare the joints properly, fill them carefully, clean the surface before residue hardens, and allow the new joints to cure before heavy use, sealing or pressure washing.
To compare suitable paving options, browse our Indian sandstone paving, Kandla Grey sandstone paving and Indian sandstone patio packs collections.
Frequently Asked Questions
What is the best jointing compound for Indian sandstone?
The best jointing compound depends on the patio. Wet mortar is traditional and strong when done well. Brush-in compound is easier for many DIY users. Resin-based jointing can give a durable professional finish, but it has stricter application conditions. The joint width, joint depth, drainage and product instructions should decide the final choice.
How long should I wait before pointing Indian sandstone after laying?
The paving should be stable before pointing. Many installers allow the bedding mortar to firm up before final jointing, but the exact waiting time depends on the bedding mix, weather and installation method. Avoid pointing if the slabs are still moving, if the bedding is soft, or if rain, frost or very hot drying conditions will affect the jointing.
What mortar mix should I use for pointing Indian sandstone?
A common fine pointing mix is 1 part cement to 3 parts plastering sand. Some installers use 4 parts sharp sand to 1 part cement for a stronger, coarser wet mortar mix. The mix should be workable but not sloppy, and it should be placed into the joints with a trowel rather than brushed across the slab surface.
Can I use a ready-mix jointing compound for Indian sandstone?
Yes, many ready-mix brush-in jointing compounds can be used with Indian sandstone, provided they are suitable for natural stone and the joint size meets the manufacturer's minimum width and depth. Always follow the application and cleaning instructions, especially the wet or dry surface requirements.
How wide should the joints be between Indian sandstone slabs?
For most riven Indian sandstone patios, joints around 10 mm to 15 mm are practical. This allows for the natural character of hand-cut sandstone edges and gives enough space for mortar or jointing compound to be compacted properly. Very narrow joints are usually less suitable for traditional Indian sandstone.
How do I remove old pointing from an Indian sandstone patio?
Loose or crumbling old pointing can often be removed with a joint scraper, weeding knife, plugging chisel or bolster. Hard cement mortar may need careful cutting with an angle grinder and mortar-raking blade. Work slowly to avoid chipping the sandstone edges, and clean all dust and debris from the joints before repointing.
Is resin-based jointing compound better than cement for Indian sandstone?
Resin-based jointing is not automatically better than cement. It can be very durable and tidy when applied correctly, but it is more expensive and often has stricter application rules. Cement mortar can also be strong and long-lasting when mixed, placed and finished properly. The better choice depends on the patio conditions and installer skill.
What happens if mortar gets on the sandstone face?
If mortar dries on the sandstone face, it can leave cement staining, haze or rough residue that may be difficult to remove. Any mortar or cement smears should be cleaned before they harden. Avoid using harsh acid cleaners on sandstone unless the product is specifically suitable for natural stone and tested first.
